Roby: Rent vs. Buy Calculator

Your family says buying is always better. Your gut says the math doesn't
add up. Roby shows you who's right.

Roby runs detailed calculations so you can see where you stand. A
mathematical illustration tool, not financial advice.

Enter your zip code, your household income, and a few details about the
home you're considering, and Roby pulls in local housing costs, tax rates,
and insurance data for your state and county. Adjust 25+ financial inputs
— from loan type to filing status to marginal tax bracket — and watch the
estimate update in real time.

SEE THE FULL PICTURE
• Month-by-month break-even timeline over up to 30 years
• Interactive charts showing estimated net position, monthly costs, and
the crossover point
• Side-by-side rent vs. buy cost comparison
• Accounts for mortgage interest deductions, PMI, SALT caps, and more

YOUR SITUATION, NOT A GENERIC ESTIMATE
• County-level median home prices and local tax rates
• Conventional, FHA, and VA loan structures with accurate mechanics
• Household income, partner income, filing status, and bracket-aware
tax modeling
• Inflation-adjusted estimates in today's dollars

THE TAX BREAK REALITY CHECK
Roby doesn't assume you'll get a "mortgage interest deduction" tax break.
It compares your estimated itemized deductions against the standard
deduction at your bracket and filing status, and tells you whether the
tax break would actually materialize at your income — or whether the
math should ignore it.

UNDERSTAND THE WHY, NOT JUST THE WHAT
Unlock 17 detailed illustration sections that go beyond the numbers:
• Required household income to stay under the classic 28% housing rule
• A stricter 25%-of-take-home second opinion
• Back-end DTI headroom, retirement-savings room, and job-loss reserve
target
• Wage-growth glide path — when a tight payment gets comfortable as
income rises
• Equity vs. invested-instead wealth comparison
• Joint-filer income shock test: what if only one of you was earning?
• Year-by-year checkpoints and landmark moments
• What-if scenarios and the levers you can pull

BUILT FOR TRUST
• One-time purchase. No subscription. No ads.
• All calculations run on your device — your data never leaves your phone
• Transparent data sources: Census Bureau, FRED, Tax Foundation, IRS
• All estimates are hypothetical, based on your assumptions. Not a
substitute for professional advice.

EXPORT & SHARE
Generate a PDF report with your full analysis to share with a partner,
family, or financial advisor.

Homeownership is a major financial commitment. See what the numbers say
for your situation.